What is a Movie Projector?

A movie projector is a device that continuously moves film along a path so that each frame of the film is stopped for a fraction of a second in front of a light source. The light source provides extremely bright illumination that casts the image on the film through a lens onto a screen.

There are four major groups of parts that make up a projector:

• Spool assembly (cambers, sprockets, claw, motor, platter)
• Lamp assembly (bulb, condenser, fan, mirror)
• Lens assembly (lens, aperture gate, shutter)
• Audio assembly (optical and digital readers, infrared LED)

In the following sections, we'll look at the first three assemblies. For information on the audio assembly, check out How Movie Sound Works.